Most laryngoscopes generally comprise a laryngoscope blade and cooperating handle, both made of metal. These two items are connected together to form a general L-shape. The handle normally serves as an enclosure for batteries for energizing an appropriate light bulb secured adjacent to the blade and connected by wires to the batteries in the handle. This bulb illuminates the patient's mouth and larynx entrance areas. A first surface on the blade itself is used to lift the tongue and mandible of a patient when the patient is in a supine position or depress the tongue and mandible of the patient if the patient is in an upright position. This action prevents the patient's tongue from obstructing the channel of vision.
While the instrument is useful for examining the larynx, its primary function is to expose the larynx in a manner to facilitate the insertion of an endotracheal tube. In this respect, the patient usually is in a supine position on an operating table with his or her head extending backwardly. In this position, as described, the first surface of the laryngoscope blade is used to lift the tongue and mandible upwardly to expose the larynx, the light on the blade being positioned beneath the lifting first surface of the blade. A second surface of the blade spaced rearwardly of the first surface is in a position opposing the upper front teeth of the patient.
In using the laryngoscope, there is almost invariably an unconscious tendency to use the upper front teeth of the patient as a fulcrum for the blade in exposing the larynx. Because of the metal construction of the blade, the patient's front teeth often are chipped by such contact and occasionally the teeth may be broken or knocked out.
In addition to the foregoing problems, conventional laryngoscopes should be sterilized after each use, or at a minimum the blade for the laryngoscope must be detached from the handle and sterilized.
In U.S. Pat. No. 3,826,248 there is shown an improved laryngoscope blade wherein that portion of the conventional laryngoscope blade defining the referred to second surface opposing the upper front teeth of the patient is removed and a plastic insert substituted for the removed portion. This plastic insert is of elastic material, capable of flexing in a manner to cushion contact with the patient's upper front teeth should the same be used unconsciously as a fulcrum when manipulating the blade to expose the larynx. This laryngoscope blade further carries a light bulb as in a conventional blade. In one embodiment, however, the light bulb is positioned in the foot of the blade and a fiber optic light conductor is used to direct the light.
While the problem of damaging teeth is solved to a large extent by the above described laryngoscope blade, there still remain problems of added expense in the actual manufacture of the blade when compound materials are used and a light bulb is incorporated in the blade.
U.S. Pat. No. 4,295,465 shows another type blade for a laryngoscope including a flange mechanically pivoted to part of the blade and biased by a spring. This flange is positioned to engage the patient's teeth and cushion action of the blade against the teeth when the teeth are used as a fulcrum.
In my prior U.S. Pat. No. Des. 242,396, I disclose a unique shaping and contouring for a disposable cover to be used to cover a laryngoscope blade. In U.S. Pat. No. 4,037,588 there is shown a disposable laryngoscope blade made entirely of plastic, this plastic material being capable of optically conducting light so that a light bulb can be arranged in the handle juxtaposed to a surface of the plastic blade. In this blade construction, in order to provide proper strength for the portion of the blade that depresses the tongue, the material has had to be fairly thick. As a consequence, the second surface portion opposing the patient's teeth corresponding to that described for conventional blades is also relatively rigid and thus the problem of damaging the patient's teeth has not been solved by this all plastic blade member.
Finally, in my patent application, Ser. No. 473,040 filed Mar. 7, 1983 and entitled LARYNGOSCOPE WITH DISPOSABLE BLADE now abandoned; and still pending application Ser. No. 472,975 filed Mar. 7, 1983 and entitled LARYNGOSCOPE BLADE AND DISPOSABLE COVER, there are described respectively a disposable laryngoscope blade made entirely of plastic but incorporating features to minimize damage to a patient's teeth, and, a disposable cover for a laryngoscope blade wherein the blade has been modified to receive the cover in such a manner that a flexible portion of the cover is defined for minimizing damage to a patient's teeth.
All the the foregoing is the closest prior art of which I am aware to my present invention.